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ipv4: fix a deadlock in ip_ra_control

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Similar to commit 87e9f03159
("ipv4: fix a potential deadlock in mcast getsockopt() path"),
there is a deadlock scenario for IP_ROUTER_ALERT too:

       CPU0                    CPU1
       ----                    ----
  lock(rtnl_mutex);
                               lock(sk_lock-AF_INET);
                               lock(rtnl_mutex);
  lock(sk_lock-AF_INET);

Fix this by always locking RTNL first on all setsockopt() paths.

Note, after this patch ip_ra_lock is no longer needed either.

Reported-by: Dmitry Vyukov <dvyukov@google.com>
Tested-by: Andrey Konovalov <andreyknvl@google.com>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
WANG Cong
2017-04-12 12:32:13 -07:00
committed by David S. Miller
parent 271a8b428f
commit 1215e51eda
3 changed files with 5 additions and 9 deletions
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2
net/ipv4/raw.c
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@@ -682,7 +682,9 @@ static void raw_close(struct sock *sk, long timeout)
/*
* Raw sockets may have direct kernel references. Kill them.
*/
rtnl_lock();
ip_ra_control(sk, 0, NULL);
rtnl_unlock();
sk_common_release(sk);
}